Australian researchers unveil a common strain capable of extracting gold from soil.

In an extraordinary finding, Australian researchers have discovered that certain strains of fungus are capable of metabolizing gold, expanding not only the toolbox of bio-indicators for metals prospecting but also the potential of naturally drawing the precious metal from tailings and mineralized soils that otherwise don't meet economic requirements for conventional mining. The applications have great potential here on Earth, but possibly even more in space.

Phytomining, the field of green mining using plants, is an intriguing area of research, as a growing number of plants, called hyperaccumulators, have been shown to metabolize metals, including nickel, zinc, copper, and now rare earths – absorbing the metals through their roots and storing them in above-ground tissues. Once mature, the plants are harvested and incinerated. The "bio-ore" ash is then processed to recover the target materials.

Nickel is currently the most studied metal in phytomining, revealing plants that can absorb up to 3% of their dry weight in the metal and are used in experimental projects across the world in Albania, Greece, and the Philippines.

Some nickel-hyperaccumulator plants have also been found to take up cobalt.

Eucalyptus trees in Australia have been shown to absorb gold particles from deep underground and deposit them in their leaves. While not widely commercialized, this property is used as a biological indicator for gold prospecting.

Some research has even suggested that plants might be able to uptake rare earths like lanthanum and yttrium, but recent studies are still in the experimental stages.

Gold is one of the most chemically inert elements – meaning it typically does not react or bond easily with other substances. However, the fungi Fusarium oxysporum has been found to extract and incorporate gold particles from the environment into their cellular structure, a process that had never been observed before.

The fact that a living organism can chemically interact with such an unreactive metal defies conventional scientific understanding and opens up new possibilities in both microbiology and mineral processing.

A surprise discovery

Creative Commons

Fusarium oxysporum is a pesky fungal species that can infest crops and includes human and animal pathogens.

This discovery originated at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia's leading national science agency.

"Gold is so chemically inactive that this type of interaction is unusual and surprising," explained Tsing Bohu, lead researcher of the study.

This unusual metabolic process, where the fungus incorporates gold into its structure, could provide new methods for gold extraction in the future.

Bohu and his team were studying microbial interactions in metal-rich environments when they encountered this surprising behavior. Initially known for its role in breaking down organic matter, Fusarium oxysporum was not expected to exhibit any affinity for metals like gold.

The team's findings expand upon the known capabilities of this fungus and lay the foundation for innovative applications in mineral exploration and extraction, particularly where conventional methods are inefficient or environmentally damaging.

Australian miners, the second-largest gold producers in the world, have taken interest in the potential applications of this discovery. One immediate use being explored is the deployment of these fungi as bioindicators to locate subterranean gold deposits. By analyzing soil samples for the presence of specific strains of Fusarium oxysporum, geologists could identify gold-rich areas with higher accuracy and less environmental impact.

This method parallels existing techniques that use natural indicators such as eucalyptus trees or termite mounds to infer the presence of underground gold. If implemented effectively, fungal prospecting could make gold exploration more sustainable, minimizing the need for invasive drilling and excavation.

Space mining potential

Perhaps the most intriguing implication of this discovery lies in the realm of space mining. As governments and private companies look to develop valuable resource extraction techniques for asteroids and other celestial bodies, biological solutions like "metabolic mineralurgy" are gaining attention.

This concept involves sending genetically modified microorganisms, such as gold-metabolizing fungi, into space to process metals directly at the source.

Traditional mining equipment is heavy, expensive to launch, and difficult to operate in microgravity environments. Fungi, by contrast, offer a lightweight, self-sustaining alternative that could efficiently extract and concentrate precious metals without human intervention.

This approach could revolutionize how future space miners access critical resources beyond Earth's atmosphere.

The convergence of biology, mining, and space technology in this discovery represents a major shift in how we think about resource extraction. Not only does it offer promising solutions to the challenges faced by modern mining – such as environmental degradation and diminishing returns – but it also aligns with broader trends in biomimicry and sustainable technology.

Using fungi to interact with and extract metals could usher in a new era of eco-friendly mining practices, both on Earth and in space. Moreover, this innovation exemplifies how seemingly unrelated scientific fields can come together to solve complex global and extraterrestrial challenges, hinting at a future where biotechnology plays a central role in planetary exploration and resource management.